With new flag `--ignore-checks-errors` user is able to
decrease severity of each individual check to warning.
Old flag `--skip-preflight-checks` now acts as
`--ignore-checks-errors=all` and will produce warnings.
Fixes: kubernetes/kubeadm#480
Automatic merge from submit-queue (batch tested with PRs 55380, 55399, 55377, 55055). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
kubeadm: use the CRI for preflights checks
Signed-off-by: Antonio Murdaca <runcom@redhat.com>
**What this PR does / why we need it**:
Add preflights checks to be performed using `crictl` and the kubernetes CRI instead of relying on docker.
**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes https://github.com/kubernetes/kubeadm/issues/285
**Special notes for your reviewer**:
**Release note**:
```release-note
kubeadm: use the CRI for preflights checks
```
@luxas PTAL
KubeletVersionCheck now able to detect if kubelet version
is higher than control plane. As this might lead to malfunctional
cluster setups, kubeadm will give warning.
Fixes: kubernetes/kubeadm#496
Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Warn user if Pod/Service networks will be accessed via proxy.
**What this PR does / why we need it**:
In environments where HTTP proxies are used, it is important
to whitelist Pod and Services network ranges in the NO_PROXY
variable, so cluster will be properly operational.
**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
**Special notes for your reviewer**:
**Release note**:
```release-note
- kubeadm will warn users if access to IP ranges for Pods or Services will be done via HTTP proxy.
```
With this change, Kubeadm will check that
/proc/sys/net/bridge/bridge-nf-call-ip6tables is set to 1 in
preflight when using IPv6. This is similar to how it currenltly checks for
bridge-nf-call-iptables.
In environments where HTTP proxies are used, it is important
to whitelist Pod and Services network ranges in the NO_PROXY
variable, so cluster will be properly operational.
